The invention relates to an internal combustion engine comprising a mechanical charger and an exhaust gas turbine coupled to the engine for transmitting power thereto.
Internal combustion engines comprising a mechanical charger and a turbo-compound consisting of an exhaust gas turbine and a reduction gear have been known in the prior art for a long time. The mechanical charger is coupled to the internal combustion engine and compresses the air required for combustion. The turbo-compound utilizes the energy contained in the exhaust gas of the internal combustion engine by means of the exhaust gas turbine and transmits the power obtained from the exhaust gas to the internal combustion engine via a reduction gear.
Particularly positive displacement machines are used as mechanical chargers in internal combustion engines. Owing to the compact type of construction of, for example, a screw charger, the latter can easily be adapted to the internal combustion engine and is distinguished, inter alia, by a high pressure ratio at low rotational speeds, high part-load efficiencies and a characteristic pumping curve having a flat profile. The power consumed by the mechanical charger, which needs to be provided by the internal combustion engine, is a disadvantage however.
The power loss due to the mechanical charger can be compensated by the turbo-compound. By virtue of a suitable design, even at low to medium rotational speeds and/or load, the turbo-compound can output more power than the mechanical charger derives from the internal combustion engine.
The patent specification DE 37 41 286 C2 describes an internal combustion engine, the mechanical charger of which is connected to the internal combustion engine by means of a belt drive. An exhaust gas turbine is coupled to the mechanical charger by means of a gear.
The publication JP 63-055325 A describes an internal combustion engine with a mechanical charger which is coupled to the internal combustion engine via a first gear drive and an exhaust gas turbine which is coupled to the internal combustion engine via a second gear drive.
It is the object of the present invention to provide an internal combustion engine of the type referred to above, wherein, however, the mechanical charger and turbo-compound can be coupled to the internal combustion engine by a simple common means.